Effect of serum proteins and osteoblasts on the surface transformation of a calcium phosphate coating: a physicochemical and ultrastructural study.
Changes occurring at the surface of a calcium phosphate coating when in contact with osteoblasts versus those in acellular solutions were analyzed. The coating studied is one with a well-documented extensive effect on short-term bone growth stimulation. Precipitates associated with original crystals and organized in a weblike structure were observed after a 3-week culture with osteoblasts. The precipitates were identified as carbonated hydroxyapatite (c-HA). In contrast, no significant surface changes were detected after immersion in an acellular serum-containing solution. However, in an acellular serum-free solution simulating the ionic composition of plasma, precipitates, identified as c-HA, were abundantly formed. Dissolution of the original coating preceded precipitation. The data support the hypothesis that dissolution of synthetic calcium phosphate ceramics is an initial step in their transformation to a biologically equivalent apatite, and suggest that both solution-mediated (dissolution-precipitation) and cell-mediated mechanisms are involved in the surface transformation.
Radin
S
S
Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia 19104, USA.
Ducheyne
P
P
Berthold
P
P
Decker
S
S
D000818:Animals; D000831:Animals, Newborn; D001798:Blood Proteins / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007101:Immersion; D008670:Metals; D008854:Microscopy, Electron; D008954:Models, Biological; D010006:Osteoblasts; D051381:Rats; D015203:Reproducibility of Results; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
D001798:Blood Proteins; D002130:Calcium Phosphates; D008670:Metals; D012996:Solutions; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous